Southern MPs  have lent their support to Prime Minister Christopher Luxon after he called an urgent in-person caucus meeting to resolve the "increased speculation" about his leadership.

Luxon has come under scrutiny again after a series of missteps and clashes with coalition partners, including calling for an MMP referendum.

He refused to speak to reporters as he made his way through Wellington Airport on Tuesday afternoon ahead of Wednesday’s meeting.

Earlier, he posted on social media: "It is clear from various media reports and conversations there is increased speculation about my leadership. It is my firm belief that division and disunity are a major distraction only 90 days out from the election.

"I also believe this distraction is unfair to the New Zealand people, and dedicated National Party candidates, supporters and volunteers, when there is so much at stake.

"For these reasons, this issue needs to be resolved quickly, and I am calling an urgent in-person Caucus meeting tomorrow at 9.30am in Wellington to resolve the issue."

National's Chris Bishop and Rima Nakhle threw their full support behind Luxon on Tuesday.

Invercargill MP and Tertiary Education Minister Penny Simmonds later joined the pair, backing Luxon “100%”.

She admitted it had been a tough week for the PM but did not believe that was enough to roll him. 

"Like any good leader, he admitted he got a few things wrong and that’s a credit to him,” Simmonds told ODT’s political editor Mike Houlahan at Otago University where she was attending a leaders’ debate on Tuesday. 

Southland MP Joseph Mooney. Photo: Richard Davison

Southland MP Joseph Mooney also said he supported Luxon and no other contenders had requested his backing.

"Any discussions will be in that caucus room, if there are any discussions to be had," he told reporters at Wellington Airport on Tuesday.

"I don't have any reason to think there's gonna be a call for a vote tomorrow."

Mooney said Luxon had himself acknowledged the "challenges" he'd faced in the past week. "That is what it is."

The Prime Minister last week endured days of mishaps and missteps and started this week inadvertently talking about three taxes his National party may introduce if back in government after the November 7 election.

He and his deputy Nicola Willis had called a news conference on Sunday to put pressure on Labour to sign up to its Budget responsibility rules, yet by his Monday morning media round, Luxon was instead explaining that a fuel excise tax, bed tax and bank tax would be on the table under a future National-led government.

Chris Bishop has previously denied plotting a challenge, insisting late last year that Christopher Luxon remained the best person to be Prime Minister. Photo: RNZ

Mixed response from MPs

National MPs were mostly keeping quiet on the matter, and had cleared their diaries on Wednesday morning - including Willis and Bishop, ranked third in the party.

Senior MP Erica Stanford, also tipped as a possible contender for the leadership, did not say a word to reporters as she arrived in Wellington on Tuesday.

Asked whether she had confidence in Luxon, she did not reply.

On Monday night, The New Zealand Herald reported National MPs had spent the day on the phones, with one confirming they had fielded "several" phone calls about a potential leadership change.

"There's going to be change in the top job. It's just a question of who is going to be it", the Herald reported the MP to have said.

Bishop, who was opening a pedestrian bridge at a railway station in Auckland with local MP Rima Nakhle on Tuesday morning, confirmed the party caucus would hold a meeting on Zoom later in the day, as earlier reported by RNZ, but denied Luxon's leadership would be on the agenda.

"I'm not talking to you about the internal machinations of what time the Zoom appointments are, but there is a meeting tonight."

He said it wasn't unusual to hold a meeting during a recess week.

It was not known if the Tuesday Zoom meeting would still go ahead.

"Last week, the PM apologised for remarks about Rotorua, and obviously there's been a bit over the MMP call, but we back our leader, and you know he's made his position clear in relation to the MMP referendum that we'll be taking that to the election. It's not going to be the focus of the campaign, as he says in his own words,” Bishop said. 

RNZ spoke to about 10 MPs on Monday night and received a mixture of responses.

Some said they would not comment, while another said they could not comment, and others denied there were any leadership murmurings or that they knew about them.

One MP said the direct quotes in the reporting suggested there must be some truth to it, and at least one MP said it was nonsense.

Bishop has previously denied plotting a challenge, insisting late last year that Luxon remained the best person to be Prime Minister.

He dismissed the suggestion there were phone calls on Monday about the National party leadership, saying he talked to caucus members "all the time about a whole range of different things".

"Yesterday was a Cabinet day, so you know clearly there were conversations between ministers and between MPs."

Bishop said it was "unhelpful" MPs were speaking to media and encouraged his colleagues not to.

"All I would say is you know people people shouldn't be talking to media like that."

Bishop said he was "getting on with the job", but then continued to answer questions from media about the leadership issue.

Nakhle also backed Luxon saying he was "the man and the boss" and she backed him "150%".

ACT leader David Seymour said he enjoyed working with Luxon and speculation about his coalition partner's leadership was a matter for the National Party.

Prime Minister and National Party leader Christopher Luxon. Photo: RNZ

Luxon says his caucus backs him

On Saturday, it was put to Luxon whether the confidence vote he called on his leadership in April this year had resulted in a caucus split of 27 votes to 22.

He responded: "I have the support of my caucus - I'm very confident in my leadership."

On Tuesday, Bishop told RNZ it wasn't worth speculating on the leadership vote, as only "two or three" people in the country knew the results for certain.

"I don't know where that reporting came from. The caucus vote is secret, and I don't know what the result was.”

It was speculation about whether Luxon was up to the job and had the backing of his caucus to stay on as leader that prompted him to test his support with a vote in April.

At the time, Luxon said that had put the rumour to bed and he had his caucus behind him. Just four months later, MPs appear to be musing about the prospect of changing leaders again.

While some spoken to by RNZ on Monday night said they supported Luxon, it wasn't unanimous.

There has been agitating since late last year from some MPs concerned Luxon's lack of personal popularity was also dragging the party vote down, and some MPs would lose their seats in Parliament if he didn't improve.

The latest RNZ-Reid Research poll in July had National down 2.1 points to 28.7%, its fourth consecutive decline in the Reid Research series and its weakest result since Luxon became leader in November 2021.

While Luxon's confidence vote win looked to have given him some reprieve, his performance in recent weeks has done little to convince concerned MPs they will be safe come election day. 

Difficult week 

Last Monday, Luxon apologised to leaders from the Rotorua Business Chamber after he criticised them for having a "parent-child mentality" and relying on government too much.

He also faced questions about his Foreign Minister Winston Peters, and why he wasn't doing anything to reprimand him after labelling his comments about a Green MP "racist".

Luxon then had to justify his use of a New Zealand Defence Force plane flying him home from a National Party fundraising dinner, and on the same day unemployment hit a record 11-year high.

On Thursday, he was using talkback radio to make a captain's call to hold a referendum on MMP, which blindsided his own caucus.

While Luxon announced the list for the upcoming election on Saturday with little disappointment or upset - keeping senior MPs and new talent happy with high enough spots to make it back to Parliament - he now faces his caucus on Tuesday night with fresh concerns.

PM since 2023

Luxon has been Prime Minister since late 2023, when National formed a coalition government with New Zealand First and ACT after the election that year.

National's support has weakened as the economic recovery has struggled to gain momentum.

Unemployment rose to 5.6% in the June quarter, its highest level in nearly 11 years, while annual inflation was 4.1%, above the Reserve Bank of New Zealand's target range of 1% to 3%.

Most opinion polls show National narrowly trailing the centre-left Labour Party, although New Zealand's proportional representation system means the November election remains too close to call.

The latest Taxpayers' Union-Curia poll put Luxon at 23.2% as preferred Prime Minister, compared with 19.8% for opposition Labour Party leader Chris Hipkins.

If National were to replace Luxon as leader, he would also cease to be Prime Minister.

A governing party has not replaced a sitting New Zealand Prime Minister between elections since 1997.

- Additional reporting by Reuters